public Packet CreateDnsReply(EthernetDatagram etherpacket, IpV4Address newAddress)
{
var ipPacket = etherpacket.IpV4;
var udpPacket = ipPacket.Udp;
var dnsPacket = udpPacket.Dns;
if (!dnsPacket.IsQuery)
{
throw new Exception("Packet should be a dns query!");
}
EthernetLayer ethernetLayer = new EthernetLayer
{
Source = etherpacket.Destination,
Destination = etherpacket.Source,
};
IpV4Layer ipLayer = new IpV4Layer
{
Source = ipPacket.Destination,
CurrentDestination = ipPacket.Source,
};
UdpLayer udpLayer = new UdpLayer
{
SourcePort = udpPacket.DestinationPort,
DestinationPort = udpPacket.SourcePort
};
DnsResourceData resourceData = new DnsResourceDataIpV4(newAddress);
DnsDataResourceRecord resourceRecord = new DnsDataResourceRecord(dnsPacket.Queries[0].DomainName,
dnsPacket.Queries[0].DnsType,
dnsPacket.Queries[0].DnsClass,
60,
resourceData);
DnsLayer dnsLayer = new DnsLayer
{
Queries = dnsPacket.Queries,
IsQuery = false,
IsResponse = true,
Id = dnsPacket.Id,
Answers = new[] { resourceRecord }
};
PacketBuilder builder = new PacketBuilder(ethernetLayer, ipLayer, udpLayer, dnsLayer);
return(builder.Build(DateTime.Now));
}
private void btnAdd_Click(object sender, EventArgs e)
{
object data = new DnsResourceDataDomainName(new DnsDomainName(txtData.Text));
if (cmbDataType.SelectedIndex == 1)
{
data = new DnsResourceDataIpV4(new IpV4Address(txtData.Text));
}
else if (cmbDataType.SelectedIndex == 2)
{
data = new DnsResourceDataIpV6(new IpV6Address(txtData.Text));
}
DnsDataResourceRecord record = new DnsDataResourceRecord(
new DnsDomainName(txtDomainName.Text),
(DnsType)Enum.Parse(typeof(DnsType), cmbType.SelectedItem.ToString()),
(DnsClass)Enum.Parse(typeof(DnsClass), cmbClass.SelectedItem.ToString())
, int.Parse(txtTTL.Text),
(DnsResourceData)data);
tabDNS.addToAnswers(record);
this.Close();
}
internal void addToAnswers(DnsDataResourceRecord record)
{
Answers.Add(record);
listAnswers.Items.Add(record.DomainName);
}
private static void TestResourceRecordIsNotCreatedWithNewLength(DnsType dnsType, DnsResourceData resourceData, int dataLengthDiff)
{
var resourceRecord = new DnsDataResourceRecord(DnsDomainName.Root, dnsType, DnsClass.Internet, 0, resourceData);
var paddingResourceRecord = new DnsDataResourceRecord(DnsDomainName.Root, DnsType.Null, DnsClass.Internet, 0,
new DnsResourceDataAnything(new DataSegment(new byte[100 + Math.Abs(dataLengthDiff)])));
Packet packet = PacketBuilder.Build(DateTime.Now, new EthernetLayer(), new IpV4Layer(), new UdpLayer(),
new DnsLayer
{
Answers = new List<DnsDataResourceRecord>(new[]
{
resourceRecord,
paddingResourceRecord
}),
});
Assert.AreEqual(2, packet.Ethernet.IpV4.Udp.Dns.Answers.Count);
Assert.AreEqual(resourceRecord, packet.Ethernet.IpV4.Udp.Dns.Answers[0]);
Assert.AreEqual(paddingResourceRecord, packet.Ethernet.IpV4.Udp.Dns.Answers[1]);
byte[] buffer = new byte[packet.Length];
buffer.Write(0, packet.Ethernet);
const int dataLengthOffset =
EthernetDatagram.HeaderLengthValue + IpV4Datagram.HeaderMinimumLength + UdpDatagram.HeaderLength + DnsDatagram.HeaderLength + 5 + 4;
ushort oldDataLength = buffer.ReadUShort(dataLengthOffset, Endianity.Big);
ushort newDataLength = (ushort)(oldDataLength + dataLengthDiff);
buffer.Write(dataLengthOffset, newDataLength, Endianity.Big);
packet = new Packet(buffer, DateTime.Now, DataLinkKind.Ethernet);
Assert.IsFalse(packet.Ethernet.IpV4.Udp.Dns.Answers.Any());
}
public Packet CreateDnsReply(EthernetDatagram etherpacket, IpV4Address newAddress)
{
var ipPacket = etherpacket.IpV4;
var udpPacket = ipPacket.Udp;
var dnsPacket = udpPacket.Dns;
if (!dnsPacket.IsQuery)
throw new Exception("Packet should be a dns query!");
EthernetLayer ethernetLayer = new EthernetLayer
{
Source = etherpacket.Destination,
Destination = etherpacket.Source,
};
IpV4Layer ipLayer = new IpV4Layer
{
Source = ipPacket.Destination,
CurrentDestination = ipPacket.Source,
};
UdpLayer udpLayer = new UdpLayer
{
SourcePort = udpPacket.DestinationPort,
DestinationPort = udpPacket.SourcePort
};
DnsResourceData resourceData = new DnsResourceDataIpV4(newAddress);
DnsDataResourceRecord resourceRecord = new DnsDataResourceRecord(dnsPacket.Queries[0].DomainName,
dnsPacket.Queries[0].DnsType,
dnsPacket.Queries[0].DnsClass,
60,
resourceData);
DnsLayer dnsLayer = new DnsLayer
{
Queries = dnsPacket.Queries,
IsQuery = false,
IsResponse = true,
Id = dnsPacket.Id,
Answers = new[] { resourceRecord }
};
PacketBuilder builder = new PacketBuilder(ethernetLayer, ipLayer, udpLayer, dnsLayer);
return builder.Build(DateTime.Now);
}
